London Borough of Hillingdon – Response to the Select Committee's 14Th and 15Th July Statements on Preliminary Conclusions
Total Page:16
File Type:pdf, Size:1020Kb
London Borough of Hillingdon – Response to the Select Committee’s 14th and 15th July statements on preliminary conclusions 24 September 2015 Introduction 1. In its statements on 14 and 15 July, the Select Committee asked for reports or proposals to mitigate further the adverse effects of the proposed scheme in Hillingdon. On 14 July the Committee asked the Promoter to explore further how the impact of the Harvil Road construction on the community could be mitigated and to report back by mid-September, including: Working with TfL and Hillingdon on their proposals to relocate the HS2 railhead to the West Ruislip London Underground (LUL) depot. Giving consideration to alternative means of road access from adjacent and nearby sites, such as the haul road to Harvil Road. 2. On 15 July the Committee also requested: Reassurance on traffic modelling. A satisfactory compromise on the Hillingdon Outdoor Activities Centre (HOAC). Significant further interventions in Hillingdon to mitigate the effect of the railway and its construction on the community additional to those already envisaged. Proposals to reduce the impact on footpath amenity during construction. Proposals to reduce the impact on local traffic during construction. Consideration of a design competition for the Colne Valley viaduct. 3. Since July the Promoter has given further consideration to all these topics and has met with both LB Hillingdon and Transport for London (TfL) both separately and together to discuss the options for minimising the adverse effects of the proposed scheme in the area. Progress has been made on measures to address all these issues. 4. This response addresses the Committee’s instructions under four main sections: SECTION 1: PROPOSED CONSTRUCTION TRAFFIC MITIGATION SECTION 2: POTENTIAL USE OF THE LUL DEPOT SECTION 3: HILLINGDON OUTDOOR ACTIVITIES CENTRE (HOAC) SECTION 4: FOOTPATHS DURING CONSTRUCTION SECTION 5: THE COLNE VALLEY VIADUCT – DESIGN, DEVELOPMENT, ENGAGEMENT AND PROCUREMENT STRATEGY 1 SECTION 1: PROPOSED CONSTRUCTION TRAFFIC MITIGATION Summary 5. In addressing the Committee’s concerns over environmental and construction impacts resulting from the proposed HS2 West Ruislip railhead and construction compound, the Promoter has focussed on three main issues: I. Reducing HGV construction traffic on the roads and improving traffic flows; II. Reducing the need for sustainable placement in the area; and III. Considering any potential role for the TfL LUL depot in delivering I and II above. 6. This work has concluded that the promotion of a construction haul road (included as part of Additional Provision 4 – AP4) and partial signalisation of Swakeleys roundabout (at a combined cost of just over £25m) will provide the most appropriate further mitigation of the traffic impacts in Ickenham resulting from the Scheme. These two measures reduce the maximum number of HGVs on Swakeleys Road (two way combined) from 1460 per day in AP2 to 500per day and will reduce the number of vehicles per hour from 73 HGVs per hour in each direction to 25 at the peak. And reduce the number of HGVs on Harvil Road from 960per day to 100 per day. It should be noted that these are all worst case scenario rather than estimated numbers. Furthermore the average junction delay at Swakeleys roundabout is reduced from 3.38/0.23 min (am/pm peak) in AP2 to 0.94/0.21min. HS2 modelling shows that the proposed Partial Signalisation of Swakeleys roundabout reduces delay in the non-HS2 traffic situation from 1.32 minutes to 0.56 minutes in the AM peak, which demonstrates a potential benefit post HS2. The proposed haul road and partial signalisation also significantly reduces the need for sustainable placement in the area and assurances have been provided in this regard. 7. A number of additional technical options have been identified which may either further reduce the traffic impacts potentially to a level whereby in consultation with the relevant authorities it may be concluded that the haul road is not needed. These include, but are not limited to, the continued investigation of options around design and re-use of material at the Copthall Cutting and changes to the construction programme in relation to the Harvil Road railhead sidings. The Promoter is committed to exploring these options and assurances will be offered in this regard. 8. In relation to the potential use of the LUL depot, the Promoter, TfL and the LB of Hillingdon have broadly agreed that the TfL depot does not provide a feasible single alternative for the HS2 west Ruislip railhead and construction compound1. Therefore the TfL depot could only be used in parallel to the proposed HS2 compound. This solution is not desirable for a number of technical, environmental and project reasons: it creates new and significant traffic impacts on West End Lane; it introduces new significant adverse effects (including noise and traffic) to Ruislip residents; it creates a bottleneck for trains removing spoil which may limit the Promoters capacity in this regard; it requires lengthy rail possessions and impacts existing services; it could add 1-2 years to the construction programme; and would cost between £60m to £90m more than the Bill Scheme to implement (excluding costs from programme delay). As such the Promoter does not propose to explore this option further. Further information on the points above is provided below and in appendix A to this report. 1 TfL and Hillingdon broadly agreed this position at a meeting on 28 August 2015 and as a result further discussions have focussed on use of the LUL depot in parallel to the HS2 railhead. 2 9. Since the Committee’s announcements the Promoter has met with TfL and Hillingdon on 6 separate occasions to discuss proposals, share modelling and discuss technical feasibilities. Overview of traffic impacts under AP2 10. The Environmental Statement to AP2 assumes a peak of HS2 construction activity in LB Hillingdon of around 1460 HGVs per day (both directions combined) along Swakeleys Road in addition to baseline traffic. This is equivalent to a maximum number of HGVs per hour one way of 73. This is a pessimistic assessment assuming construction activities at compounds occur concurrently In reality, the estimate of construction traffic (rather than the most likely worst case predicted presented in the ES) is for a peak period of HS2 HGV construction traffic 0f 1060 HGVs gradually decreasing to a much lower rate of less than 200 vehicles per day for the majority of the construction programme. This trend is summarised in Figure 1 below. The geographical distribution of HS2 HGV construction traffic is shown diagrammatically in figure 2 below. Figure 1. AP2 HGV traffic along Swakeleys Road, LB Hillingdon, throughout the construction phase. This demonstrates the significant higher AP2 daily flows (of 1460 per day) compared with the expected flow shown by the histogram. Figure 2. Distribution of HS2 AP2 HGV construction traffic in LB Hillingdon2. 2 Approximately 73 HGV per hour (compared to the Baseline) have been assumed to enter Swakeleys roundabout from the A40 eastbound and turn to the north on Swakeleys Road between 0800 and 1800. For the same time periods, it has 3 11. Under AP2 the average junction delay (mins) at Swakeleys roundabout is expected to be 3.38 and 0.74 for the AM and PM peak respectively, compared to a baseline (without HS2 scenario) of 1.32min and 0.23min. 12. All of the above modelling 1) assumes that existing (non HS2 traffic) does not divert due to the additional HS2 HGV traffic, 2) excludes the likely mitigating impacts of Local Traffic Management Plans which would be agreed with the highway authority and 3) ignores any reduction in HGV numbers as the design for the scheme is refined. As such, these represent a reasonable but worst case assessment in this location. Promoter’s mitigation proposals 13. Following the Committee’s statement the Promoter has explored a number of possible traffic improvements and proposes to bring forward two options in combination: a haul road enabling a direct route from the A40 to the West Ruislip site located between Harvil and Breakspear Roads and partial signalisation of Swakeleys roundabout. 14. In combination these two proposals will significantly mitigate the traffic impacts above. 15. The proposed haul road (which has been included in AP4) will connect at its southern end with the eastbound slip road adjacent to the A40 Western Avenue / B467 Swakeleys Road roundabout. The southern section of the haul road will pass to the west of - and parallel to - The Drive. The northern section will pass through Uxbridge Golf Course and land to the west of Harvil Road. The haul road will cross Harvil Road to enter the HS2 worksite. Figure 3. Location of the proposed haul road been assumed that 73 HGV will exit Swakeleys corridor via the A40 / Swakeleys Road roundabout and turn to the west on the A40 (westbound). 4 16. The haul road will be constructed during the HS2 enabling works. It will take approximately one year to construct. It will be in operation for up to seven years and will take a further year to remove. The haul road will provide an alternative route to replace the use of the B467 Swakeleys Road and Harvil Road, reducing construction traffic along both roads (see below for more detail). The construction traffic route via the A40 Western Avenue, the B467 Swakeleys Road and Harvil Road will be retained, although subject to very substantially lower construction traffic flows than reported in Part 1 of the SES and AP2 ES. 17. New signal-controlled junctions will be provided temporarily at both ends of the haul road, with part signalisation of the NW and SE arms of Swakeleys roundabout between the A40 and Swakeleys Road.